The invention relates to exercise fitness equipment, and more particularly to a crank assembly therefor.
The joint between a crank arm and a crankshaft is one of the most important joints on a piece of fitness equipment. On an upright stationary bike, for example, this joint supports the loads generated by the exercise and the user's body weight. The crank arm may be mounted to the crankshaft along a tapered square. The crank arm is typically steel or aluminum, and the crankshaft is typically steel. Assembly and disassembly of the parts reveal markings, which indicate less than optimal surface contact.
The present invention arose during continuing development efforts in the above technology and provides a simple, economical system for maximizing surface contact between the crank arm and the crankshaft, distributing the loads across a large area.